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Posted by Pedro on May 05, 19100 at 12:00:24:
I want to see what people have to say about evolution.
Firstly, lets revisit the definition of a theory : A theory is a model that describes past findings and predicts future findings. A good theory is simple, describes all the findings made in the past and can be used to makes good predictions about future findings. According to this definition, the theory of evolution, is ‘good’.
Evolution is the theory that living things change from one generation to the next, i.e. that children are not exact copies of their parents. The theory of evolution claims that through small changes from one generation to the next, species evolve into different varieties and from one species into another. The common companion to the theory of evolution is the Darwinian theory, which says that things evolve in response to changes in their environment.
I studied Geology at University for 3 years and am quite familiar with the theory of evolution. I have observed that as you dig down through a sequence of rocks the kinds of fossils that you find change. In one layer you might find the carbonaceous remains of plants unlike any that exist today, as you go up you will find the opalized bones of oddly shaped fish, and in the upper layers you will find the remains of dinosaurs, then mammals and in the most recent sediments, human beings and other contemporary animals. Indeed, the geologic time scale is broken into periods and epochs according to the types of fossils that are found in the sedimentary rocks formed during that period.
Within and between geologic periods it is possible to observe changes to the animals and plants. Take trilobytes as an example. These little beasties have left heaps of fossil imprints because they were something like a cross between a slater and a roach, and were prone to fossilization because they often lived amongst compacting sediments. It is possible to dig down in a column and find a set of trilobyte remains that change systematically according to the depth at which they are found. There are changes to the shape of the carapace, with trilobytes found at great depth being generally simpler than ones found further up. In some places it is possible to see that the trilobytes developed compound eyes, perhaps because they were living in places where there was light. By looking further up the same sequence, it is sometimes possible to see that the eyes fade away, possibly as the environment changed so that there was no longer light.
Trilobyte morphology changed in such a regular and systematic way that people can tell which stratigraphic sequence a rock was taken from by the type of trilobyte imprinted in it.
There are methods which are used to estimate the age of rocks by essing certain types of radioactive decay. The ages given by these ytical methods can be cross checked against the ages given by the fossil record. This sort of cross checking is commonplace and works very well. These days people tend to date rocks in the field, by eye (using fossils), and check this date by ysing a rock sample with a laboratory method. Of course, these methods are relative rather than absolute, but even if the ages given are wrong, the rocks appear to be very very old.
Fossil dating is used most frequently by geologists working in the oil mining industry. If the predictions made by the fossil dating methods were not good, then they would not find oil. Oil exploration geologists are generally pretty successful. Are they just lucky or is the theory of evolution capable of making useful predictions ?
If one were to argue against the theory of evolution one would have to find another explanation for the patterns observed in the fossil record, or dispute the very existence of the fossil records. Now, the fossil record has been observed by many thousands of people, and anyone with access to a nice cliff face can take a look at it themselves. To dispute the fossil record one would probably need to say something like “I don’t believe that what I see with my eyes is true”.
Any comments ?
Pedro